compile java files with ant for incremental builds

Meson doesn't support incremental builds for java, so delegate the java
compilation to Ant if available.

src/api-impl/build.xml

@@ -0,0 +1,19 @@
+<project name="api-impl" default="dist">
+	<!-- the Ant build is intended to be started from Meson. The properties will be set using commandline parameters -->
+
+	<target name="compile">
+		<mkdir dir="${build}"/>
+		<javac srcdir="${srcdir}" includes="${includes}" destdir="${build}" includeantruntime="false" debug="true">
+			<compilerarg line="${javaargs}"/>
+		</javac>
+	</target>
+
+	<target name="dist" depends="compile">
+		<jar jarfile="${jarfile}" basedir="${build}"/>
+	</target>
+
+	<target name="clean">
+		<delete dir="${build}"/>
+		<delete dir="${dist}"/>
+	</target>
+</project>

src/api-impl/meson.build

@@ -1,4 +1,4 @@
-hax_jar = jar('hax', [
+srcs = [
 	'android/Manifest.java',
 	'android/R.java',
 	'android/accounts/Account.java',
@@ -591,11 +591,32 @@ hax_jar = jar('hax', [
 	'javax/microedition/khronos/opengles/GL11Ext.java',
 	'javax/microedition/khronos/opengles/GL11ExtensionPack.java',
 	'org/apache/harmony/xnet/provider/jsse/SSLParametersImpl.java',
-              ],
-              java_args: [
+]
+java_args = [
 	'-bootclasspath', bootclasspath,
 	'-source', '1.8', '-target', '1.8',
 	'-encoding', 'UTF-8',
 	'-Xlint:-deprecation', # we implement deprecated APIs
 	'-h', join_paths(dir_base, 'src/api-impl-jni/generated_headers')
-              ])
+]
+
+ant = find_program('ant', required: false)
+
+if ant.found()
+	hax_jar = custom_target('hax',
+	                        output: 'hax.jar',
+	                        command: [ant,
+	                                 '-buildfile', files('build.xml'),
+	                                 '-Dbasedir=' + builddir_base,
+	                                 '-Dsrcdir=' + meson.current_source_dir(),
+	                                 '-Dincludes=' + ','.join(srcs),
+	                                 '-Djarfile=@OUTPUT@',
+	                                 '-Dbuild=@PRIVATE_DIR@',
+	                                 '-Djavaargs=' + ' '.join(java_args),
+	                        ],
+	                        depend_files: srcs + ['build.xml'],
+	)
+else
+	hax_jar = jar('hax', srcs,
+	              java_args: java_args)
+endif

src/test-runner/build.xml

@@ -0,0 +1,19 @@
+<project name="test-runner" default="dist">
+	<!-- the Ant build is intended to be started from Meson. The properties will be set using commandline parameters -->
+
+	<target name="compile">
+		<mkdir dir="${build}"/>
+		<javac srcdir="${srcdir}" includes="${includes}" destdir="${build}" includeantruntime="false" debug="true">
+			<compilerarg line="${javaargs}"/>
+		</javac>
+	</target>
+
+	<target name="dist" depends="compile">
+		<jar jarfile="${jarfile}" basedir="${build}"/>
+	</target>
+
+	<target name="clean">
+		<delete dir="${build}"/>
+		<delete dir="${dist}"/>
+	</target>
+</project>

src/test-runner/meson.build

@@ -1,4 +1,4 @@
-test_runner_jar = jar('test_runner', [
+srcs = [
 # test-runner
 	'android/test/ActivityInstrumentationTestCase2.java',
 	'android/test/ActivityInstrumentationTestCase.java',
@@ -56,13 +56,35 @@ test_runner_jar = jar('test_runner', [
 # this was part of dalvik but got removed at some point
 	'dalvik/annotation/BrokenTest.java',
 	'dalvik/annotation/SideEffect.java',
-                     ],
-                     build_by_default: false,
-                     link_with: [hax_jar],
-                     java_args: [
+]
+
+java_args = [
 	'-bootclasspath', bootclasspath,
 	'-source', '1.8', '-target', '1.8',
 	'-encoding', 'UTF-8',
 	'-Xlint:-deprecation', # we implement deprecated APIs
 	'-h', join_paths(dir_base, 'src/api-impl-jni/generated_headers')
-                     ])
+]
+
+ant = find_program('ant', required: false)
+
+if ant.found()
+	test_runner_jar = custom_target('test_runner',
+	                        output: 'test_runner.jar',
+	                        command: [ant,
+	                                 '-buildfile', files('build.xml'),
+	                                 '-Dbasedir=' + builddir_base,
+	                                 '-Dsrcdir=' + meson.current_source_dir(),
+	                                 '-Dincludes=' + ','.join(srcs),
+	                                 '-Djarfile=@OUTPUT@',
+	                                 '-Dbuild=@PRIVATE_DIR@',
+	                                 '-Djavaargs=' + ' '.join(java_args + ['-classpath', hax_jar.full_path()]),
+	                        ],
+	                        depend_files: srcs + ['build.xml', hax_jar.full_path()],
+	)
+else
+	test_runner_jar = jar('test_runner', srcs,
+	                          build_by_default: false,
+	                          link_with: [hax_jar],
+	                          java_args: java_args,)
+endif